Entitled Red Serpent, and set in 1904 Paris, ten years before the events of The Last Express, it would have been an early adventure of Robert Cath (still in medical school) and his best/worst friend Tyler Whitney (upgraded in this version to Cath’s half-brother — a change I don’t think I’d make today).

The plot bears a more-than-slight resemblance to The Da Vinci Code, which would be published the following year. No plagiarism was involved. I’d guess that Dan Brown and I had been reading the same pseudo-historical “research,” including Holy Blood, Holy Grail by Baigent and Leigh (who did, in fact, sue Brown for plagiarism, and lost). Whereas Brown treated their theory seriously, my approach was more tongue-in-cheek.